Boron containing fuels



United States Patent 0. F

3,130,097 BORON CONTAINING FUELS Folsom E. Drummond, Washington, D.C.,assiguor to The Commonwealth Engineering Company of Ohio, Dayton, OhioNo Drawing. Filed Sept. 20, 1961, Ser. No. 140,169 4 Claims. (Cl.149-42) This invention relates to improved fuels and methods forincreasing the calorific Value of fuels, especially those comprisingpowdered lower atomic weight elements such as boron, beryllium andlithium.

The invention is particularly useful in providing a fuel which iscomposed of powdered metal and oxygen-supplying agents which uponburning release a large amount of heat as measured in B.t.u. per poundof fuel burned.

It is an object of this invention to provide a fuel which, in the formof a solid fuel, is useful as a propellant for missiles, rockets, andfor releasing high temperature gases upon burning. The solid fuel of theinvention further may be used as a fuel for jet-driven aircraft,turbines, and the like, as employed in the fields of aviation, militaryequipment and rail transportation operations.

These and other objects and advantages of the invention will becomeapparent to those skilled in the art from the following description ofthe invention.

The present invention is based upon the provision of a solid fuel of thecharacter described and which is composed of a mixture of low atomicWeight metals and their compounds, together with oxygen-supplyingmaterial to promote the combustion once started.

The invention is illustrated further by the following typical examplesExample I Percent by Weight Diborane 50 Beryllium metal powder (particlesize 1-5 micrns) 30 Lithium perchlorate 20 Example 11 Pentaborane 40Beryllium metal powder (Ex. I) 35 Lithium perchlorate 25 Example IllDecaborane 60 Beryllium metal powder (Ex. I) 30 Potassium chlorateExample IV Diborane (liquid) 4O Beryllium metal powder (Ex. I) 2OCellulose nitrate 10 Lithium perchlorate 30 Example V Diborane (liquid)45 Boron metal powder (average size 1 micron) 30 Lithium perchlorate 25A means? Ice Patented Apr- 1964 Example VI Percent by weight Diborane(liquid) 35 Lithium metal powder (average size 1 micron) 50- Lithiumperchlorate 15 Example VII Diborane (liquid) 40 Lithium metal powder(Ex. VI) 35 Cellulose nitrate 15 Lithium perchlorate 10 Example VIIIDiborane (liquid) 35 Beryllium metal (Ex. I) 35 Cellulose nitrate 25Sodium perchlorate 5 Preferably the sol-id fuel mixture of borane (inliquid state) is suitable admixed with metal powder and chloratematerial and compressed (2000 psi.) to a solid fuel mass. Thetemperature of the mixture is kept low enough so that the boranecompound used is liquid and atmosphere pressure. Where desired, the fuelmixture may be prepared in the form of a pasty mass by mechanicallymixing and blending the ingredients together. The fuel thus compactedmay be ignited by an electrically heated Wire partially embedded in themass.

Borane (boron-hydrogen) and powdered low atomic weight metal constitutethe essential constituents of the fuel. Oxygen is supplied forsupporting the combustion by the chlorate. Other decomposable compoundswhich release oxygen to promote the combustion of the borane and metal,where desired, may be used.

Boron burned as diborane (13 1-1 which is liquid at 112 C. atatmospheric pressure, releases approximately 35,000 B.t.u.s per pound ofthe borane burned. Pentaborane (R I-I which is a colorless liquid atordinary temperatures, is highly combustible and is handled at lowtemperatures (46 C.) or at temperatures and pressures to maintain itliquid.

The production of diborane by hydrogenation of a compound of boron maybe carried out as described in US. Patent 2,965,450 and US. Patent2,582,268. In place of diborane the trimer boron hydrogen sulfide (B S Hmay be used.

Examples illustrative of such fuels are as follows Example IX Percent byweight Boron hydrogen sulfide (B S l-I 50 Beryllium metal particles(averaging 1 micron in diam.) 30 Lithium perchlorate 20' Example X Boronhydrogen sulfide 45 Boron metal particles (average size 1 micron) 30Lithium perchlorate 25 Where the fuel is desired to have a lower densityor greater porosity, combustible fillers, such as cellulose cotton, e.g.cellulose nitrate or acetate or the like may be incorporated. Such afiller addition is exemplified in Example IV supra. The proportion ofconstituents may be varied to produce the desired burning rate andcalorific value as required. By increasing the proportionate amounts ofborane and low atomic weight powdered metal in the fuel, higher B.t.u.values are obtained. A preferred range of borane, powdered metal andchlorate in the fuel, based on the total weight of the fuel mass, isborane 20-60%; powdered low atomic weight metal 30-50%; and chlorate25-40%.

Beryllium, which has an atomic weight of 9.02 when burned in metalpowder form releases approximately 28,000 Btu. per pound of metalburned. Boron, which has an atomic weight of 10.82 when burned, releasesapproximately 25,000 B.t.-u. per pound of metal burned. Lithium, havingan atomic weight of 6.94 when burned, releases about 18,000 Btu. perpound.

Oxygen is supplied by the use of a chlorate and preferably use is madeof a low atomic weight metal perchlorate such as lithium perchlorate.The perchlorate releases approximately 60% of the compound upondecomposition as oxygen which sustains the combustion of the fuelmixture.

The meaning of the term low atomic weight in this specification refersto elements having an atomic weight below 12, and exemplified by boron,beryllium and lithium.

Powdered mixtures of the fuel may be ignited in the conventional manneror use may be made of a spark plug, electrically heated wire or fuseinsert as desired.

This application is a continuation-in-part of my copending applicationSerial No. 830,985, filed August 3, 1959, now US. Patent No. 3,070,472.

It is understood that various materials may be substituted for those setforth in the above examples when the same perform the same function andlike results, and the proportionate amounts of the constituents may bevaried to suit the use being made of the fuel. and variations are deemedto be contemplated as coming Such changes 4 within the scope and spiritof this invention, the same being more particularly set out in theappended claims.

What is claimed is: 1. A fuel consisting of the following in parts byweight:

Percent by weight Diborane 40 Beryllium metal powder 20 Cellulosenitrate 10 Lithium perchlorate 30 100 2. A fuel consisting of thefollowing in parts by weight: Percent by weight 4. A rfuel consisting ofthe following constituents in parts by weight:

Parts by weight Diborane 35 to Metal particles of a metal selected fromthe group consisting of beryllium, boron and lith ium and mixturesthereof 20 to Alkali metal perchlorate 5 to 30 Cellulose nitrate 10-25References Cited in the file of this patent UNITED STATES PATENTS3,070,472 Drummond Dec. 25, 1962

4. A FUEL CONSISTING OF THE FOLLOWING CONSTITUENTS IN PARTS BY WEIGHT: